aboutsummaryrefslogtreecommitdiff
path: root/util/mmap-alloc.c
diff options
context:
space:
mode:
Diffstat (limited to 'util/mmap-alloc.c')
-rw-r--r--util/mmap-alloc.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 54793a5..5cd7f71 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -50,10 +50,11 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
#if defined(__powerpc64__) && defined(__linux__)
/* On ppc64 mappings in the same segment (aka slice) must share the same
* page size. Since we will be re-allocating part of this segment
- * from the supplied fd, we should make sure to use the same page size,
- * unless we are using the system page size, in which case anonymous memory
- * is OK. Use align as a hint for the page size.
- * In this case, set MAP_NORESERVE to avoid allocating backing store memory.
+ * from the supplied fd, we should make sure to use the same page size, to
+ * this end we mmap the supplied fd. In this case, set MAP_NORESERVE to
+ * avoid allocating backing store memory.
+ * We do this unless we are using the system page size, in which case
+ * anonymous memory is OK.
*/
int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : fd;
int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE;